linux-kernel - Re: [PATCH] efi/arm: fix allocation failure when reserving the kernel base

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Message-ID: <20190821061027.GA2828@linux-8mug>
Date:   Wed, 21 Aug 2019 06:10:52 +0000
From:   Chester Lin <clin@...e.com>
To:     Ard Biesheuvel <ard.biesheuvel@...aro.org>
CC:     Russell King - ARM Linux admin <linux@...linux.org.uk>,
        "guillaume.gardet@....com" <guillaume.gardet@....com>,
        "ren_guo@...ky.com" <ren_guo@...ky.com>,
        "mingo@...nel.org" <mingo@...nel.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "geert@...ux-m68k.org" <geert@...ux-m68k.org>,
        "rppt@...ux.ibm.com" <rppt@...ux.ibm.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        Chester Lin <clin@...e.com>, Gary Lin <GLin@...e.com>,
        Juergen Gross <JGross@...e.com>, Joey Lee <JLee@...e.com>,
        "linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] efi/arm: fix allocation failure when reserving the kernel
 base

On Tue, Aug 20, 2019 at 03:28:25PM +0300, Ard Biesheuvel wrote:
> On Tue, 20 Aug 2019 at 14:56, Russell King - ARM Linux admin
> <linux@...linux.org.uk> wrote:
> >
> > On Fri, Aug 02, 2019 at 05:38:54AM +0000, Chester Lin wrote:
> > > diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> > > index f3ce34113f89..909b11ba48d8 100644
> > > --- a/arch/arm/mm/mmu.c
> > > +++ b/arch/arm/mm/mmu.c
> > > @@ -1184,6 +1184,9 @@ void __init adjust_lowmem_bounds(void)
> > >               phys_addr_t block_start = reg->base;
> > >               phys_addr_t block_end = reg->base + reg->size;
> > >
> > > +             if (memblock_is_nomap(reg))
> > > +                     continue;
> > > +
> > >               if (reg->base < vmalloc_limit) {
> > >                       if (block_end > lowmem_limit)
> > >                               /*
> >
> > I think this hunk is sane - if the memory is marked nomap, then it isn't
> > available for the kernel's use, so as far as calculating where the
> > lowmem/highmem boundary is, it effectively doesn't exist and should be
> > skipped.
> >
> 
> I agree.
> 
> Chester, could you explain what you need beyond this change (and my
> EFI stub change involving TEXT_OFFSET) to make things work on the
> RPi2?
>

Hi Ard,

In fact I am working with Guillaume to try booting zImage kernel and openSUSE
from grub2.04 + arm32-efistub so that's why we get this issue on RPi2, which is
one of the test machines we have. However we want a better solution for all
cases but not just RPi2 since we don't want to affect other platforms as well.

Regards,
Chester